DE1593681A1 - Heat stabilized polyamides - Google Patents

Description

Heat Stabilized Polyamides The invention relates to heat stabilized polyamides Polyamides by adding organic compounds containing copper and a process for their manufacture.

It is known that polyamides, such as those made from caprolactam, Hexamethylene diammonium adipate and xexamethylene diammonium sebacate are produced can be used for a wide variety of technical purposes. But you have that Disadvantage that they in the Ilitze an oxidative damage and 'one by the Temperature-related degradation of the polymer are subject. As the oxidative attack initially limited to the surface, it mainly occurs in molded parts with large Surface, such as fibers and foils, are particularly pronounced.

For example, in the case of unstabilized fibers, the oxidative attack at temperatures above 150 oO already after 2 to 3 hours to a reduction in strength of more than 50%, the oxidative and thermal degradation of test rods takes with it 4 mm in diameter at this temperature takes 16 to 24 hours.

The additive is used to prevent thermo-oxidative damage a multitude of compounds has become known. These are preferably copper compounds, Alkali halides, phosphorus derivatives, aromatic amines, phenols and aminophenols.

However, a large number of the proposed compounds are not capable of any to produce sufficient effects. Substances such as aromatic amines, phenols or aminophenols, seem to be effective in that they are very light in themselves Oxidizable substances protect the polyamide from oxidation or the one. management delay the degradation mechanism. This stabilization is limited; therefore essentially atif the avoidance of loss of testability and reductions in molecular weight.

Of particular interest as thermal stabilizers are copper and Copper compounds. which have been proposed in the most diverse variations, z. B. colloidal copper, copper salts of organic or inorganic acids, copper complexes with ß-diketones and oxyazo compounds, aliphatic amines or aliphatic Polyamines, ethylene urea or biguanide.

All of the above compounds have the disadvantage that they either do not have sufficient heat stability or are poor within the polyamides can be distributed and therefore for reasons of better distribution and processing. must be provided with additional lubricants.

The purpose of the invention is to avoid these disadvantages.

The invention is based on the object of heat-stabilized polyamides to develop in which compounds are used as stabilizers that do not contain any require additional use of a lubricant.

It has been found that polyamides are particularly heat stabilized and, moreover, have other valuable properties when the polyamides 0.05 to 2% by weight of a copper-containing organic compound of the general formula CUx (Ra NH-cO-NH-R2-NH-R3) Jy, where R1 is a straight aliphatic hydrocarbon chain with 6 to 20 carbon atoms, R2 is a straight aliphatic hydrocarbon chain with 2 to 6 carbon atoms, R3 a hydrogen atom or the radicals -CH2-CH2-NH2 and -CH @ -CH @ -CH @ -NH @. x is 0.5 or 1 and y is 1 or 2 equivalents of an acid mean.

The addition can be at any stage of manufacture or Processing of the polyamides takes place insofar as care is taken. that a homogeneous Distribution is guaranteed.

Instead of the iodide compounds, other compounds can also use this Type, such as 3. Acetate or propionate, together with an alkali or alkaline earth iodide contained as an additive in the polyamide. be.

The advantage of the polyamides composed according to the invention is there in that the heat treatment not only does not reduce the molecular weight becomes, but even increases. In addition, these additives result in a particularly favorable one Further processing of the polyamides, especially in injection molding, so that a no additional use of lubricants is required.

The polyamides stabilized in this way can be used in a known manner to stimulate crystallization, Dyes or fillers, such as. B.

Glass fibers, or well-known oxidation stabilizers, such as. B.

Di-ß-naphthyl-p-phenylenediamine, are added.

The copper-containing organic compounds added as stabilizers are new and have not yet been described. The invention is therefore further the The object of the invention is to develop a process for the production of these compounds.

It has been found that one can use organic compounds containing copper (Copper complexes) of the general formula Cux (R1-NH-CO-NH-R2-NH-R3) Ay where R1 is a straight aliphatic hydrocarbon chain with 6 to 20 carbon atoms, R2 one straight aliphatic hydrocarbon chain with 2 to 6 carbon atoms, R3 a hydrogen atom or the radicals -CH2-CH2-NH2 and -CH2-CH2-CH2-NH2, A organic or inorganic acid residues, such as. B. acetate, propionate, chloride, bromide, iodide, cyanide and phosphate, x denotes the values 0.5 or n and y denotes 1 or 2 equivalents of an acid, can be obtained if one condensation products of urea, unbranched aliphatic Reacts amines and a lower aliphatic polyamine with copper salts.

For the preparation of copper complexes of poorly soluble copper salts, like copper aodide, it is advisable to start with the copper complex with an easily soluble one Produce copper saiz and this by a subsequent double conversion with to convert the corresponding alkali salts to the desired copper complex or in the presence of the corresponding alkali salts with easily soluble copper salts to work.

The effect of the products according to the invention is particularly surprising as a heat stabilizer for polyamides.

The blue-green to brown-yellow waxy ones obtained according to the invention Products also show fungicidal effects and can either be in the form of their powder, as an emulsion as a suspension or dissolved in a suitable solvent as a pesticide can be used with a fungicidal effect.

It has been shown that it is advantageous to use the copper complexes obtained to be mixed with finely divided silica gel, graphite or molybdenum disulfide. This creates easily pulverizable and therefore easy to dose products.

Example 1: With the addition of water and acetic acid as molecular weight regulator poly-tc ', -caprolactam was polymerized in the VK tube, once without a Ritz stabilizer and the other time worked with the addition of 0.5% copper complexes became.

The material contained 9.5% extracts and was processed in the usual manner spun into threads that have been drawn. The threads were two hours at 170 0c treated in a circulating air drying cabinet. From the material was before and after the heat treatment determines the relative solution viscosity and the residual strength.

The values can be found in Table 1. The were used as a stabilizer used copper propionate complex according to Example 3 and the copper acetate complex according to Example 4 produced.

Table 1 Stabilizer # rel. # rel. untreated still 2 hours residual pem Heat solid to 170 ° C 0.5% Copper propionate complex 2.10 2.46 95 +0.5% Potassium iodide 0.5 X copper acetate 2.17 2> 72 complex 2.17 2.72 91 0.% potassium iodide without stabilizer 2, 32 1.31 40 # rel = rel. Solution viscosity in 93% H2S04 a # 1% solution of the polyamide Example 2: Polyamide in the form of cylinder gray matter was in a rotating drum with the stabilizers listed in Table 2 mixed and homogenized using an extruder. The material became standard test rods splashed. The test bars were stored in a circulating air drying cabinet at 150 ° C. At fixed intervals, the bars were removed from the drying cabinet and after the tensile strength is determined after cooling in a tearing machine. As permanent the times were viewed. in which the tensile strength due to the heat treatment not more than. 20% compared to the zero sample.

The values can be found in Table 2. They were used as stabilizers used copper complexes prepared according to the following examples: Copper propionate complex according to example 3 copper acetate complex according to example 4 copper iodide complex according to example 5.

Table 2 Polyamide stabilizer resistant to (hours) Polycaprolactam unstabilized 16 polycaprolactam + 0.2% copper acetate 96 polycaprolactam + 0.2 % Copper acetate + 0.2% potassium iodide 336 polycaprolactam + 0.2% N, N'-di - @ - anphthylp-phenylenediamine 168 polycaprolactam + 0.2 7% copper propionate complex 504 polycaprolactam + 0.2% Copper propionate complex + 0.2% potassium iodide 1008 polycaprolactam + 0.2% copper acetate complex 336 polycaprolactam + 0.2% copper acetate complex + 0.2% potassium iodide 1008 polycaprolactam + 0.4% copper acetate complex + 0.4% potassium iodide over 2000 polycaprolactam + 0.5 % Copper acetate complex (30 f0 glass fiber + 0t5% potassium acid reinforced over 2000) Polyhexamethylene adipamide without stabilizer 24 polyhexamethylene + 0.4% copper acetate complex adipic acid amide + 0.4% potassium iodide over 2000 polycaprolactam + 0.6% copper iodide complex over 2000 polycaprolactam + 0.6% copper acetate complex (mixed with silica gel) + 0.4% potassium ioidide over 2000 A urea condensate is used as the starting product prepared according to DWP 33 240 in the following way: 269 g (1 mol) of a fraction of unbranched primary aliphatic amines with 16 to 20 carbon atoms (average C18) and 120 g (2 mol) of urea were added while passing a gentle stream of nitrogen through it heated by the reaction vessel to 140 ° C. for 16 hours, with 0.95 mol of ammonia were split off.

The melt was then cooled to 100 ° C. and the mixture was stirred added to 2 liters of water and vigorously until it cools down to room temperature stirred further. The unreacted urea largely dissolved out. The deposited solid monoalkylurea was filtered off with suction, again with 1 liter Boiled water. again suctioned off, washed and at a temperature of 55 ° C dried.

A) 156 g (1/2 mol) of the monolkylurea obtained in this way were with 37 g (1/2 mol) propylenediamine in 350 cm3 xylene heated under reflux for 24 hours, whereby 1/2 mole of ammonia was split off. After distilling off the xylene under 183 g of condensation product remained as a solid residue under reduced pressure.

B) 312 g (1 mol) of the same monoalkylurea were with 131 g - (1 mol) Dipropyl @ ntriamine in 700 cm3 xylene heated to 140 oC and 24 hours held at this temperature, with 0.95 mol of ammonia being split off. To after distilling off the decaline under reduced pressure, 425 g of condensation product remained as a solid residue.

Example 3: 1000 g of the urea condensates produced under A. were dissolved in 2 l of ethanol. 307 g of copper propionate were added to this solution dissolved in a mixture of 200 cm3 of water and 500 cm3 of ethanol. The solvent was then distilled off in vacuo in a water bath. The residue was dirty green in color. Yield: 1290 g.

Example 4; 1000 g of the urea condensate produced under 3 were dissolved in 2 l of ethanol. To this solution were 205 g of copper acetate in a Mixture of 150 cm3 of water and 400 cm3 of ethanol were dissolved. It fell blue-green products äus. The entire mixture was concentrated in vacuo in a water bath. The residue was a dirty green color. Yield about 1190 g.

Example 5: 263 g of the copper complex according to Example 4 were used in 500 cm3 ChloroSorm dissolved. An aqueous solution of 83 g of potassium iodide was added to this solution given and-the whole mixture shaken vigorously.

The water was separated from the chloroform layer, which was had colored dark brown. The chloroform was then distilled off in a water bath. The residue was brown in color.

Yield: 290 g.

Example 6: 74 g of the compound prepared according to A were under Warming dissolved in 200 ml of ethanol. The hot solution was added to this solution with stirring Added a solution of 17 g of copper chloride in 100 ml of ethanol.

A light blue precipitate formed which, after cooling, was sucked off, washed with ethanol and dried in a vacuum drying cabinet at 60 ° C.

Yield: 78 g, 45 g of the product thus obtained were added with heating dissolved in 500 ml of chloroform and with a solution of 17 g of potassium iodide in 100 ml Water shaken. The mixture turned brown. Then it was through careful stirring in of an aqueous sodium bisulfite solution until it is completely discolored reduced. The aqueous phase was separated off and the chloroform solution was washed with water and the solvent is distilled off.

After the residue had been dried in a vacuum drying cabinet at 60.degree 42 g of a pale colored product were obtained.

Example 7: 370 g 'of the compound prepared according to A were under Brwarming dissolved in 1 l of ethanol. The hot solution was added to this solution with stirring of 200 g of copper acetate in 1 l of water. An initially light blue color formed Precipitation that gradually turned dark brown over mixed colors. After this Cooling was filtered off with suction, washed with ethanol and in the vacuum drying cabinet 60 0C dried.

Yield: 390 g Example 8: 370 or compound prepared according to A. were dissolved in 1 l of ethanol with warming. This solution was added with stirring added the hot solution of 170 g of copper chloride in 1 l of ethanol.

A light green precipitate formed which, after cooling, was sucked off, washed with ethanol and dried at 60 ° C. in a vacuum drying cabinet.

Yield: 480 g. Example 9: In a kneader were alternately in portions a total of 20 g of the complex salt according to Example 5 and 10 g of Arosil were added.

The kneader was heated to 140 ° C. during this process. After 20 minutes it was the mixing. completed. The product was fine-grained and light brown in color Hue.

Claims (4)

Claims: 1. Heat-stabilized polyamides, characterized by a content of 0.05 to 2% by weight of copper-containing organic compounds of the general formula Cux (R1-NH-CO-NH-R2-NH-R3) Jy, where R1 is a straight aliphatic Hydrocarbon chain with 6 to 20 carbon atoms, R2 a straight aliphatic Hydrocarbon chain with 2 to 6 carbon atoms, R3 a hydrogen atom or the radicals -Ch2-Ch2-Nh2 and -CH2-CH2-CH2-NH2, x the values 0.5 or 1 and y 1 or 2 mean equivalents of an acid. 2. Heat-stabilized polyamides according to claim 1, characterized in that that they use other compounds of this type in place of the iodide compounds, such as. B. acetate or propionate, together with an alkali or alkaline earth metal anodide. 3. Process for the production of organic compounds containing copper (Copper complexes) of the general formula Cux (R-NH-CO-NH-R2-NH-R3) Ay, where R1 is a straight aliphatic hydrocarbon chain with 6 to 20 carbon atoms, R2 one straight aliphatic hydrocarbon chain with 2 to 6 carbon atoms, R3 a Hydrogen atom or the radicals -CH @ -CH2-NH2 and -CH2-CH2-CH2-NH2 A organic or inorganic acid residues, such as. B. acetate, propionate, chloride bromide, iodide, cyanide and phosphate, x denotes the values 0.5 or 1 and g denotes 1 or 2 equivalents of an acid, characterized in that one condensation products from Urea, unbranched aliphatic amines and a lower polyamine with copper salts implements. 4. The method according to claim 3, characterized in that for the production of copper complexes of poorly soluble copper salts, such as. B, copper iodide, first the copper complex with a readily soluble copper salt and this by double reaction with the corresponding alkali salts in the desired Converts copper complex or that one with easily soluble copper salts in the presence the corresponding alkali salts works.